Monday, 9 November 2015

About the Glaze tests

Recently I had a chat with my friends and fellow potters, and the conversation turned to glazes and glaze tests. We all have favorite ways to test, record and document the glazes....and during the conversation I promised to write a blog about my way of testing and documenting.
As some test tiles just came out of the kiln, it is a perfect opportunity to tell you about it.
First, about the test tiles:
This is my extruder die ( for 2 different extruders):

It has smooth and rounded top edge and a few notches to show how the glaze behaves on the textured surface. I tend to extrude a big batch in one go, to last me at least a year. That way I always have tiles on hand.
When I extrude the tiles, I score a line at the bottom of the vertical surface, just above the angle. That makes it easy to break the bottom off for filing:
Once I forgot to do the score line and had to use the angle grinder  for this step.
I store the tiles on A4 size 3 mm thick MDF board fitted with stapled elastic on both sides:

It helps to cut all the tiles the same size :)
I use the same format to write the recipes on the A4 page, and that way I have clear visual reference:

The further benefit is that the tiles are always stored together with the others tested in the same batch,so the whole series is easily viewed together.

It is easy to pull the tiles out for the close comparison. All of them have their ID number written on the back, so they will not be mixed up.

Because the tiles are fired vertically, I can see how the glaze moves in the firing and how it behaves on the top lip. How the glaze breaks over, or covers the raised line is the good indicator of how will it show textured surfaces.

I have made several sturdy MDF boxes with handles and slots for the tile trays.They can be stored vertically or horizontally, and are easily and safely carried to workshops.
One box stores (I think) 640 glaze tests.

Slots in the box are easily made with glueing and stapling strips of 3 mm MDF at equal distances.

Someone said that the main difference between the Scientist and the Artist is that Scientists keep (better) notes.